The use of hydroponics for the growth of plants is well known in the art and many different types of systems have been proposed. Generally, with hydroponics, a non-soil medium is utilized and the plant gathers the required nutrients from a liquid to which the roots are exposed. The original arrangement was adapted from conventional growing systems wherein the plants grew from containers lying in a horizontal plane. Lights were generally suspended above the plants and containers. While this system functions well, a substantial amount of energy is required for the lighting and accordingly, the economic return can only be justified with relatively high value plants.
More recently, systems have been developed which utilize a drum carrying a non-soil medium in which the plants grow with the drum rotating about a light source thereby maintaining a substantially constant distance between the plants and light. Since the light is effective through the full 360° of rotation, less total wattage is required for a given number of plants. In such an arrangement, liquid is generally provided at a trough located at the bottom of the drum into which the plants or at least their root systems are immersed to thereby provide the required moisture and nutrients.
One problem which has been encountered in prior art rotating drum systems is the maintenance of correct light intensity. The light intensity is exponentially related to the distance between the plant and the light. As there must be sufficient room for the plants to grow, the light source must be a certain distance away from the plants. While this distance may be suitable when the plants are substantially fully grown, the light intensity may be insufficient for the plants when they are young.
In order to overcome the above, it would be desirable to provide for an arrangement wherein the lamps can be easily interchanged.
A further problem which arises is the heat developed by the lights. Since the bulb is typically incased in a tube, the heat build up is substantial and any mounting arrangement should provide for maximum ventilation through the tube.